Method of exhausting lamps



Nov. 5;, i957 J. F, GILMQRE E'-Ai..V 2,312,223

METHOD oF Ein-IAUSTING LAMPS Filed May l5, 1954 Sheets-Sheet 1 Y Eig- Y,fra/.17) aufs-ep vF24/human sarpzy @my -r/Panrcanp l Heavy nu Nov. 5, 1957 J. F. GILMORE HAL METHOD oF EmAUsTING 'LAMPS Filed may 1s. 1954 United States Patent Op METHODOF EXHAUSTING LAMPS John F. Gilmore, Verona, and Thomas H. Heine, Cedar Grove, N. J., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 13, 1954, Serial No. 429,587

4 Claims. (Cl. S16-22) The present invention relates to exhaust and, more particularly, to a method of exhausting fluorescent lamps.

During the exhaust of fluorescent lamps on a conventional automatic 48 head machine the sealed lamp may be loaded into an exhaust head, for example, at either station 47or 48. From stations l through stations 42 the lamp may be continuously under vacuum. The lamp may be baked in a suitable oven to remove water vapor and deleterious occluded gases from stations 3 through station 22. From stations "25 through station 40 ythe lamp cathode may be treated. Mercury may be introduced into the lamp by a conventional mercury doser at station 30. From stations 37 through 40 the lamp may be arced.y At station 43, the evacuated lamp may be filled with an inert gas from a suitable supply through a pressure regulator and the sweep. The lamp may be tipped off at station 44 and unloaded automatically from the exhaust machine at stations 45 and 46.1,

During the exhaust of fluorescent lamps on such a conventional exhaust machine one of the defects encountered is the contamination of the sweep (a pipe extending from the exhaust head to the rotary portion of the exhaust valve) by deleterious gases which have been pumped out of the lamp and remain in the sweep immediately prior to the gas filling position at station 43. In the present automatic exhaust machine these contaminants are pushed back into the lamp by the fill gas at the gas filling station.

Another defect of the present exhaust practice is the Vfailure to prevent slow leakers which have not been pinched oft, from contaminating the fill gas line and thus adversely affecting the quality of the lamps thereafter indexing into the gas fill station 43.

Hence, it has been found advantageous according to the invention to pinch the lamp oil and to flush the sweep (prior to the gas fill station) to remove any contaminants remaining in the sweep. Further the invention proposes that after the flushing operation the sweep alone be filled to a predetermined pressure at the sweep filling station. When the filled sweep has indexed beyond the gas fill station, the pinch clamp can be reopened thus filling the lamp. Thus a slow leaker is isolated from the till gas system and cannot `contaminate the till gas and adversely affect the quality of succeedingl lamps indexing into the fill station.

'In its general aspect the present invention has as its general aspects an improved method of exhaust for fluorescent lamps.

AA specific object of the invention is an improved method of fluorescent lamp exhaust which method prevents the return of contaminants to the evacuated lamp during the gas fill.`

Another object is an improved method of fluorescent lamp exhaust which method isolates leakers from the gas fill system and prevents contamination of the gas fill system. y

Other objects of the present invention Will become ice apparent to those skilled in the art to which it appertains as the description thereof proceeds and from direct recitation from the context.

Referring to the drawing in which like numerals of reference indicate similar parts throughout the several views:

Fig. l is a plan diagrammatic view of a modified automatic fluorescent lamp exhaust machine on which the method of the invention may be practiced.

Fig. 2 is a view similar to Fig. l, but showing aconventional automatic fluorescent lamp exhaust machine.

Fig. 3 is a vertical sectional view of an exhaust machine head along the line III-III of Fig. l in the direction of the arrows, at station "37 the sweep flushing station.

Fig. 4 is a view similar to Fig. 3 along the line IV--IV of Fig. 1 in the direction of the arrows at station 43,1 the lamp gas filling station of the machine of Fig. l.

Referring now to the drawing in detail, and particularly to Figs. l and 2, the reference numeral 10 designates a conventional multiple head automatic fluorescent lamp exhaust machine. This machine 10 has a turret 12 rotatable on a pedestal (not shown) and for carrying a plurality Iof fluorescent lamp exhaust heads 14 (for example 48 in the 'present showing of Fig. 2). The turret 12 is indexable through a like number of work stations by a conventional indexing mechanism (not shown).

A conventional fluorescent lamp 20, fragmentarily shown in Figs. 3 and 4 has a'vitreous tubular envelope 22 sealed at each end to a filamentary mount24 having at least an emission material coated filamentary cathode 25. One of the filament mounts 24 is suitably provided with an exhausttube 26 for insertion into an exhaust headr14, as hereinafter explained.

At either station-s "47 or "48 the sealed fluorescent lamp 20 may be loaded into an exhaust head 14 of the machine 10. From station l0 through station 42" the lamp 20 may be vcontinuously exhausted. The lamp 20 may be baked at a uniform bulb wall temperature (from top to bottom) of 350 to 400 C. in a suitable oven indicated diagrammatically in Fig. 2. The oven extends from stations "3 through 2'and may be handily provided with oven entrance 'and exit extensions to help retain the heat.

From stations 25 through station "40 the cathode 25 l of the fluorescent lamp 20 may be ysuitably treated by passing a current through both cathodes causing the evolution of CO2 gas.

It is necessary to heat the emission material hot enough to insure its complete Vbreakdown into carbon dioxide and theoxides of barium, strontium and calcium. Overheating must be avoided as this will drive active emission material oil the cathode, resulting in short lamp life and envelope end discoloration. Undertreating must be avoided as this will cause CO2 to be evolved in the iinished lamp, resulting in hard starters, high voltage lamps, discolored ends, and wigglers.

At station ,"30 the lamp 20 may be dosed with a predetermined amount'of distilled mercury by a conventional reactor type doser mechanism 28 (Figs. 1-4).A

The temperature of the envelope 22 at mercury dosing should be above C. When the mercury is added to the hot lamp 20 it partially vaporizes and flushes residual deleterious gases out of the lamp 20 and into a sweep 30, a pipe extending from the head 14 to a rotary portion 40 of an exhaust valve 50. The valve 50 has a lower stationary portion 42. Further the vaporized mercury provides an ioniz'able medium for subsequent arcing.

The lamp 20 may be arced from stations 37 through 40. VIn the lamp arcing positions a high voltage is applied acrossthe lamp 20 (to one leg of each cathode 25 in one position and to the opposite leg on the next posif APatented Nov. 5, 19757' tion) and an arc is formed/with aid of spark coils placed along (but nottintcontact with) the lower portion of the lamp 20. The arcing further activates the emissive coating on the end turns of the cathode 2,5.

` At--stationsf43i the lamp 20 maybe given the proper 4inert gas fill, suitably argon, at a pressure from 3.0 to 3.6 `millimeters of mercury from a suitable inert gas supply Modified exhaust machine The above-described exhaust schedule may be modified according to the method of the invention as practiced on a modified exhaust machine 100. The lamp 20 (Fig. l is now evacuated from station "1 through 36. BetweenI stations 36" and 37, the sweep flushing station, a pinch clamp valve 60 (Figs. 3 and 4) on the lamp exhaust head 14 'may `be closed, as hereinafter explained.

At station 37 the sweep may be back fiushed with an inert gas, such as argon, thus removing any residual deleterious gases already removed from the lamp 20 but still remaining in the sweep 30.

The purpose of flushing the sweep 30 is to provide a clean `path for the subsequent inert gas fill of the sweep 30 at station 42, as hereinafter explained. The sweep 30 may be back flushed with about 15 mm. of an inert gas, such as argon, through a gas fill constriction. From stations "38 through 41 the inert gas mixes with the deleterious Vgases in the sweep 30 and is evacuated, leaving a clean sweep into which the fill gas may be introducedat station "42.

Thepinched od lamp 20 is arced as above described from stations f37 through 40. At station 42 the clean sweep 30 is filled (for example if the lamp 20 is a 40 watt slimline T12 48 fluorescent lamp) with an inert fill gas, such as argon, to a pressure in the neighborhood of about 100 millimeters of mercury. Between stations 42 and 43 the pinch clamp 60 on the lamp exhaust head 14 is opened, as hereinafter described, and the sweep` 30 indexes above a plugged segment of the stationary portion 42 of the valve 50, thus sealing off the filled sweep 30. At station `43" (Figs. 1 and 4) the lamp 20 is filled to a desired pressure in the range of 3.0 to 3.6 millimeters of mercury from the sweep 30. At station "44 the lamp 20 may be tipped ofi and unloaded from the machine at either station 45" or 46.

Turret The turret 12, Figs. 3 and 4, has a hub 102 handily carried on a ball or roller bearing `104 and connected to a hollow shaft 106. The turret 12 is driven in any suitable manner by a conventional indexing mechanism (not shown). The turret 12 also carries the upper movable section 40 of the rotatable vacuum valve 50, the lower stationary portion 42 of which is mounted on a stationary frame portion 108 of the exhaust machine 100. yIn Fig. 3 a line 110 extends from a suitable argon supply (not shown) ofthe exhaust machine 100 through a suitable fitting, and through said stationary portion 42 where it registers with the sweep 30 extending through the rotary portion 40 of the valve 50, a suitable fitting, a trap 114 to the pinch clamp valve 60. The pinch clamp valve 60 is mounted on a head mounting plate 116 carriedV on the periphery of the turret 12. In Fig. `3 aline 111 at station 36," an exhaust station, connects the stationary portion 42 of the valve 50 to an exhaust system (not shown) of the machine 1 00.

Valve This pinch clamp valve 60 is provided with a housing 1,20 in which is positioned a normally open rubber tube 1.22. adapted tvfb@ Closed by a pinch Clamp bell, Crank lever 1.24 .Meteosat Qfthi lever 124, either manually or automatically, as by engagement thereby with an operating arm 126 when moving outwardly toward `the bell crank lever 124 (when viewed in Fig. 3), pinches off the rubber tube 122, thus closing `the pinch clamp valve 60.

The activation of the arm 126 is accomplished by energization of a relay 130, supported on a bracket 131. This bracket 131 is mounted on a hub on a stationary rod 132, within the shaft 1,06.` The relay draws the armature 134 thereof to the right (when viewed in Fig. 3) and pulls an arm 136 of a bell crank lever 138 inthe same direction by means of a connecting link 140, to rotate the operating roller carrying arm 126 of said bell crank lever about its pivot 142. It will be understood that the relay 130 is energized by a cam switch (not shown) on the main drive shaft (not shown) of the exhaust machine 100. This cam switch is indicated diagrammatically in Fig. 3.

Head

As shown in Figs. 3 and 4, each of the heads 14 has a compression rubber assembly 150. This assembly comprises ahollow body 152 threadably secured to the mounting plate 116 and provided with a lower threaded portion for carrying thereon a hollow cap 154. The cap 154 has a suitable operating handle 156. A compression rubber 158 is seated on a hollow ball bearing insert 160 between the lower portions of the body 152 and the cap 154. Y

As shown in Figs. 3 and 4 the exhaust tubulation 26 of a lamp 20 may be inserted through the cap 154, the insert and the rubber 158 and secured thereat by the rotation of the handle 156, thus compressing the rubber 158 about the upper end of the tubulation 26.

The mercury doser 28 may be mounted by means of a threaded connection on the upper end of the hollow portion of the body 152 of a head 14. A line 162 connects the rubber tubing 122 of the pinch clamp valve 6l) with the hollow interior of the body 152 of a head 14.

As shown in Fig. 4 the modified exhaust machine 100 is provided with a stationary cam mounting plate (Fig. 4) secured to the hub on the fixed post 132. This plate 170 carries a stationary pinch clamp lever operating cam 172 which opens the pinch clamp valve 60, as a head 1,4 indexes from station 42, the sweep filling station, to station 43, the lamp filling station. It will be understood that the line (which in the conventional exhaust machine 10 connects the argon supply, not shown, to the stationary portion 42 of the vacuum valve 50) is plugged at station 43 the lamp lling station (Fig. 4).

Sweep Flushing nection 110 (Fig. 4), the valve 50 and into the sweep 30 where the inert gas begins to mix with the deleterious Vgases remaining in the sweep 30.

lt will be understood that each of the sweeps 30 for each of the 48 heads 14, of the modified exhaust machine 100, does not necessarily have a specific volume but that each of the sweeps 30 has the same identical volume. In this way a specified pressure of inert gas for the sweep flush, gives the same resultant fill pressure in the lamps 20.

From stations 38 through "41 the sweep 30 containing the admixture of deleterious gases and the inert ushing gas'is subjected (Fig. 3) to the exhaust system (not shown) ofthe modified exhaust machine 100. When the lamp 20 indexes from station 4l the last pumping station, into station 42 the lsweep filling station, the

sweep 30 is completely evacuated and free of deleterious gases.

Gas lling At station 42 the sweep filling station, an inert gas, such as argon, at a pressure of about 100 mm. of mercury is admitted through a line 180 (Fig. 4) similar to the line 110 of Fig. 3, and the valve 50 and into the clean sweep 30.

Between station 42 the sweep filling station and station 43 the lamp iilling station the operating lever 124 of the pinch clamp valve 60 encounters the stationary cam 172 (Fig. 4) thus opening the valve 60 and admitting the desired pressure of inert gas in the range of 3.0 to 3.6 mm. of mercury, through the connection 162 and the head 14 into a lamp 20.

It will be understood that since the number of exhausted lamps per hour produced by the modified exhaust machine 100 is in the neighborhood of 800 lamps per hour, the index time for the machine 100 is approximately 3600 divided by 800 or about 41/2 seconds from index to index. With an initial pressure in the neighborhood of 100 mm. of mercury of inert gas in the sweep 30 and this index time of about 4% seconds, the desired final inert gas ll for a lamp 20 of about 3.0 to 3.6 mm. of mercury can be obtained.

Although a preferred embodiment of the method of the invention has been disclosed it will be understood that modilications may be made within the spirit and scope of the invention.

We claim:

l. The method of gas iillingv an exhausted fluorescent lamp on an automatic exhaust machine having a rotatable turret for carrying a plurality of heads thereon which are each provided with a sweep and are indexable through a like number of work stations, comprising closing ol said exhausted lamp from its sweep, filling said sweep with an inert iiush gas, exhausting said sweep containing admixed fiush and deleterious residual gases, opening said lamp to said clean sweep, filling said clean sweep and said lamp with a final gas ll, tipping off said lamp and unloading said lamp from said machine.

2. The method of gas filling an exhausted uorescent lamp on an automatic exhaust machine having a rotatable turret for carrying a plurality of heads thereon which are each provided with a sweep and are indexable through a like number of work stations, comprising closing off said exhausted lamp from its sweep, filling said sweep with an inert ush gas, exhausting said sweep containing admixed ush and deleterious residual gases, lling said clean sweep with an inert gas, opening said lamp to said iilled sweep to fill said lamp with a final gas iill, tipping of said lamp and unloading said lamp from said machine.

3. The method of processing a iiuorescent lamp comprising loading a sealed lamp into a head of an automatic exhaust machine having a rotatable turret for carrying a plurality of said heads thereon which are each provided with a sweep and are indexable through a like number of work stations, exhausting said lamp, simultaneously exhausting and baking said lamp, again exhausting said lamp, simultaneously exhausting and cathode treating said lamp, closing off said exhausted lamp from said sweep, filling said sweep with an inert iiush gas, exhausting said sweep containing admixed iiush and deleterious residual gases, opening said lamp to said clean sweep, filling said clean sweep and said lamp with a final gas fill, tipping oit said lamp and unloading said lamp from said machine.

4. The method of processing a fluorescent lamp com prising loading a sealed lamp into a head of an automatic exhaust machine having a rotatable turret for carrying a plurality of said heads thereon which are each provided with a sweep and are indexable through a like number of work stations, exhausting said lamp, simultaneously exhausting and baking said lamp, again exhausting said lamp, simultaneously exhausting and cathode treating said lamp, closing off said exhausted lamp from said sweep, filling said sweep with an inert ush gas, exhausting said sweep containing admixed ush and deleterious residual gases, lilling said clean sweep with an inert gas, opening said lamp to said filled sweep to fill said lamp with a final gas fill, tipping off said lamp and unloading said lamp from said machine.

References Cited in the file of this patent UNITED `STATES PATENTS 1,704,981 Lebrun Mar. 12, 1929 2,247,513 Marshaus July 1, 1941 2,249,098 Van Sant July 15, 1941 2,284,036 Bol May 26, 1942 2,334,718 Lowry et al Nov. 23, 1943 2,454,745 Quinn Nov. 23, 1948 

